Three-time world surfing champion Andy Irons has died at age 32, reportedly of dengue fever.

Irons was yesterday found dead in a Dallas/Fort Worth hotel room. He was returning home to Hawaii from Puerto Rico, where he withdrew from a surfing competition due to illness. According to media reports, Irons told his family that he had caught dengue fever while in Portugal.

Portugal recently reported a surge in the kinds of mosquitoes that transmit dengue, but there is no known dengue outbreak there or in Western Europe. Dengue is endemic in Puerto Rico. Dengue symptoms can appear as soon as three days after the bite of a dengue-virus-carrying mosquito, but it isn’t clear how long Irons was in Puerto Rico — nor it is confirmed that Irons truly suffered from dengue.

Another surfer said that both he and Irons had fallen ill with similar symptoms while in Portugal, and that there was a lot of mosquito activity in the area.

Dengue is the fastest growing mosquito-borne illness in the world. Mosquitoes capable of spreading the disease are increasing their range, likely due to global warming.

There are four strains of dengue virus. Infection with any of the strains causes a high fever AND at least one other symptom:

Symptoms usually are milder the first time a person has dengue. The most dangerous thing about dengue is that a second infection — with a different strain of the virus — can trigger dengue hemorrhagic fever (DHF). As Irons has traveled to many tropical nations during his extraordinary career, there would have been many opportunities for prior dengue infection. Former world champion surfer Mark Occhilupo told the Sydney Morning Herald that Irons had come down with dengue several years ago in Bali.

Dengue hemorrhagic fever is a sneak killer, although with proper medical care the death rate is about 1%. DHF appears AFTER a first bout of fever, usually on day 4 or day 5 of a dengue illness. The infection causes fluid to leak from small blood vessels, which can lead to profound shock, organ damage, and death.

Even if Irons truly had dengue, it’s not clear that this was the cause of death.Investigators reportedly found powerful prescription painkillers in his hotel room, suggesting a possible overdose if the athlete had been self-medicating for dengue-related pain. An autopsy is being performed today.

Compounding the tragedy of Irons’ death is that his wife is seven months pregnant.